Deep wound infections resulting from open wound orthopaedic and trauma procedures are both costly to the health care system and physically (and emotionally) debilitating for the patient. Currently, there are no FDA approved surgical wound irrigants for cleansing surgical wounds and open trauma surfaces, other than sterile saline. Surgeons will prescribe the addition of antibiotics (such as Bacitracin) or a dilute hypochlorite solution (dilute bleach) in an effort to improve the cleansing capabilities of sterile saline irrigants. However, surgeons will also agree that there is little science behind this custom, with the effectiveness of antibiotics delivered via short term exposure being particularly suspect. It is unlikely that complete bacterial kill is achieved under such conditions and there is no improvement in the solution's ability to remove contamination and bacteria (or endotoxins resulting from dead bacteria) from the surface of the tissue.
There have been some published studies regarding the ad hoc use of commonly available surfactants (such as castille soap) and disinfectants (such as betadine and hydrogen peroxide) applied directly to deep wounds. These studies indicate that some of these approaches can have a negative impact upon wound tissue healing. In Europe, there has been some clinical work with solutions containing a biguanide disinfectant (such as polyhexamethylene biguaninde or PHMB). Indications are that improper use (delivery) or dosage can lead to complications (such as anaphylaxis in rare instances).
Another approach related to managing orthopaedic wounds has been the addition of antibiotics to bone cement. Its widespread prophylactic use in the US is restricted due to concerns regarding development of a resistant bacterial strain in the patient. The FDA has contraindicated use of these products for prophylactic use, limiting it only to use in two stage revisions. In addition, recent guidance from the American Academy of Orthopaedic Surgeons (AAOS) is discouraging wide spread prophylactic use of these products. As with the ad hoc addition to sterile saline, the addition of antibiotics to bone cement, does not result in an improvement to wound cleansing or healing directly related to contamination, bacteria, or bacterial endotoxin, removal.
Current rates of post-operative deep infection vary by surgical procedure, reporting clinician, and hospital. Current estimates, however, are approximately as follows: Primary hip—1%; Revision hip—3%; Primary knee—1.5%; Revision knee—5% (recent information indicates that the infection rate in revision knee surgery has increased significantly in the last two years); Trauma 1M rods—5 to 15%; Trauma Ex-fix pins—15% or greater.
The current standard of care for orthopaedic implants with an established deep infection is a “two-stage” procedure wherein the initial implant is removed, the infection is brought under control over a period of 6-8 weeks, and then a new implant is inserted. With the exception of ex-fix pins, the removal and replacement of the implant entails two complex and potentially challenging surgeries with the patient being in a compromised condition (either bed ridden or on crutches with braces) for 6 to 8 weeks. The patient is exposed to a traumatic experience and the health care system costs can be in excess of $60,000 (US estimates). In severe situations, re-infection can occur, and sadly, even amputation in relatively rare situations.
Although efforts in the 1980's and 1990's to reduce infection rates associated with total joint replacements have met with success in developed nations, recent trends such as the increase in infection rates associated with revision knee procedures is a reason for concern. It has been speculated that this trend could be due to less experienced surgical staffs (as the need to manage increasing numbers of revision cases grows) and the rise of resistant organisms such as methycillin resistant staph. Infection rates associated with surgery are significantly higher in developing nations. As total joint surgery expands into developing countries, a robust, yet easily deployed, wound cleansing program will be a major part of the successful adoption of joint replacement in those markets.
The clinical need for satisfactory wound cleansing and healing in open (compound fracture) trauma situations is universal world wide. In many cases the delay between the event and proper wound management/stabilization prior to musculoskeletal reconstruction can be several hours. These situations provide a significant challenge for wound decontamination, which is still debated at major orthopaedic trauma meetings. As such, there is clinical need for a satisfactory composition, and system for delivering that composition to a wound site, wherein the composition effectively neutralizes or removes pathogenic and/or infectious agents upon contact with the wound surface.